 Erected as a subgenus ("Anceus") of "Xenochironomus" , "Axarus" was subsequently renamed and elevated to generic status .The Connecticut River in the eastern United States harbors locally dense populations of two "Axarus" species, both currently undescribed.These populations are interesting in that they are restricted to specific larval habitat (varve clay and sometimes rotting wood) and thus there is genetic structure between populations in the river .